With evolution of the messaging system, end users, in practice, may use a plurality of terminals to log on the messaging service system. For instance, the user may use a Personal Computer (PC), a Personal Digital Assistant (PDA) or a cell phone, etc.
A conventional method for realizing a multi-terminal session is described below.
First, two parties in communication use an INVITE command to set up a session and negotiate media information to be used in the session. Then, the media information is interacted in accordance with the negotiated media capability. Lastly, a BYE command is used to terminate the session. If one party or the two parties has multiple terminals to join in the session, this situation is handled by a Globally Routable User Agent Uniform resource identifier (GRUU).
Specifically, a public URI carries a “gr” parameter. This parameter is generated using a device ID, such as MAC address of the terminal, at the time when the terminal is being registered on line. URI plus “gr” gets GRUU. When GRUU is adopted, routing entities and service entities in the network are all required to support GRUU, which may ensure a correct routing to a specific terminal. If GRUU is not supported, “gr” parameter is neglected during the processing. When both parties support GRUU, multiple terminals can be switched to one another or simultaneously join the session.
It is discovered, during the process of this invention, a user B is able to identify each terminal of user A using a plurality of terminals. For instance, when terminal 1 of user A is communicating with user B and terminal 2 of user A requests to join the session, the session between terminal 1 of user A and user B will be disconnected first, and a conference is set up. Terminal 2 of user A, terminal 1 of user A and user B will join the conference to conduct a session. Therefore, the conventional method for multi-terminal session treats each terminal of a multi-terminal user as a single entity. When multiple terminals are participating the session, the session might probably be disconnected in order to set up a conference, which may deteriorate the user experience.